ML20236U482
| ML20236U482 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 07/24/1998 |
| From: | Jeffery Wood CENTERIOR ENERGY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 1-1168, 50-346-98-06, 50-346-98-6, NUDOCS 9807300195 | |
| Download: ML20236U482 (5) | |
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Davis-Besse tJuclear Power Station g gp 550f North State Route 2 Oak Harbor Ohio 43449-9760 John K. Wood 419-249-2300 Mce President. Nuclear Fax. 419-321-8337 i
Docket Number 50-346 License Number NPF-3 I
Serial Number 1-1168 July 24, 1998 United States Nuclear Regulatory Commission l
Document Control Desk l
Washington, D.C. 20555-0001
Subject:
Response to inspection Report Number 50-346/98006 (DRS)
Ladies and Gentlemen:
Toledo Edison has received Inspection Report Number IR 50-346/98006 (Toledo Edison Log Number 1-3967) and the enclosed Notice of Violation issued on June 9,1998. The violation pertains to the untimely identification of an event which took place during maintenance work on a steam generator. Toledo Edison provides the attached response to the subject violation. The submission date of this reply was extended from July 9,1998 to July 24,1998, based on discussions with the Region III Projects Branch Chief for the Davis-Besse Nuclear Power Station (DBNPS) following the Alert on June 24,1998, at the DBNPS; and based on discussions with the DBNPS Senior Resident inspector and the Region III Engineering Specialists Branch I Chief on July 20,1998.
Should you have any questions or require additional information, please contact Mr. James L. Freels, Manager - Regulatory Affairs, at (419) 321-8466.
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cc: A. B. Beach, Regional Administrator, NRC Region III A. G. Hansen, DB-1 NRC/NRR Project Manager S. J. Campbell, DB-1 Senior NRC Resident inspector Utility Radiological Safety Board l
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1 Docket Number 50-346 License Number NFF-3 l
Serial Number 1-1168 Attachment i
Page J Repiv to a Notice of Violation (50-346/98007-01)
Alleced Violation During an NRC inspection conducted from April 22 - May 7,1998, a violation ofNRC requirements was identified. In accordance with NUREG-1600, " General Statement of Policy and Procedure for NRC Enforcement Actions," the violation is listed below:
10 CFR 50, Appendix B, Criterion XVI, " Corrective Action" requires that measures be established to assure that conditions adverse to quality, such as failures, malfunctions, deficiencies, deviations, defective material and equipment, and nonconformances are promptly identified and corrected.
Contrary to the above, a condition adverse to quality was not promptly identified and corrected, in that on April 15,1998, a Potential Condition Adverse to Quality Report (PCAQR) was not initiated after an unauthorized wire brush, used to clean steam generator B primary manway stud I
holes, failed resulting in the uncontrolled introduction of carbon steel wire bristles into the primary coolant system. Further, on April 18,1998, and April 19,1998, a PCAQR was not initiated when wire bristles were identified by video camera to be present on the steam generator tube sheet and bottom bowl. In addition, on April 25,1998, eddy current examinations identified a wire bristle wedged inside a steam generator tube. Although a PCAQR was initiated to address i
the effect of the metal on the fuel, control rod drive mechanisms, pump seals and other primary system components, until prompted by the inspector, no actions were initiated to address the noncompliance with the applicable maintenance procedure which authorized only stainless steel or nylon brushes.
This is a Severity Level IV violation (Supplement I).
Resnonse to Alleced Violation 50-346/98006-01 Reason for Violation When the carbon steel brush failed during use on April 14,1998, it was not realized by the worker that the wrong type of brush had been used. A carbon steel brush has the same general appearance as a stainless steel brush, and unless a side-by-side comparison is performed, the material of the brush is not obvious. At one point in time, carbon steel brushes were exclusively l
used to clean the carbon steel stud holes of the steam generators at Davis-Besse. A change was l
made to the applicable procedure to only use stainless steel or nylon brushes because they are I
more durable. It appears that all carbon steel brushes were not removed from the steam generator tool boxes after their use was discontinued.
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Docket Number 50-346 License Number NPF-3 Serial Number I-1168 Attachment Page]
it is common knowledge of the Framatome Technology, Inc. (FTI) personnel involved in this work that carbon steel brushes may fail in the manner observed and should not be used. The steam generator B manway and diaphragm were still in place at the time of the brush failure, which prevented any wire bristles from entering the steam generator at that time. The worker believed the failed brush that was taken from the steam generator tool box was of the proper material. Another brush, this one stainless steel, was retrieved from the same tool box, and work was continued aller cleaning up the bristles from the failed brush. Since steam generator B was not open at the time of the brush failure, no concerns about foreign material entering the steam generator existed. No procedural violation was known to have existed at this time. Per the FTI Quality Assurance (QA) Plan in place for the elesenth refueling outage, no documentation of the failed tool was required.
It is believed that the wire bristles were transported into steam generator B via the filter hose that was positioned under the stud hole to collect the debris generated during cleaning. The same filter hose was used to draw any debris out of the stud hole. Once the manway and diaphragm were removed, a shield door was installed, and the same filter hose was connected to the shield door to ventilate the steam generator. If any of the wire bristles remained in the filter hose after the brush failed, they could have entered the steam generator once the hose was connected to the shield door. Any loose wire bristles remaining on the work platform could also have been introduced into steam generator B during installation of the remotely-operated eddy current equipment.
When the wire bristles were identified by video camera to be present on the steam generator B tube sheet on April 18,1998, they were entered into the FTI Open Systems Log for Steam Generator Activities as required by the FTI QA Plan to document the as found condition. This entry ensured the wire bristles would be removed prior to closcout of the steam generator in accordance with the FTI Field Procedure for Steam Generator Closcout. No further actions were required at this time in accordance with the FTI QA Plan. Toledo Edison personnel were informed of the presence of the wire bristles in steam generator B on April 21,1998. A plan was developed to obtain a sample of these wire bristles from the steam generator to identify how long the bristles had been in the reactor coolant system, while maintaining personnel dose as low as reasonable achievable. On April 23,1998, a sample of the wire bristles was obtained and delivered to Radiation Protection personnel. On April 25,1998, after determination that the wire 1
bristles had not been in the steam generator during reactor operation, meaning they were 1
introduced during the current refueling outage, Potential Condition Adverse to Quality Report (PCAQR) 1998-0781 was initiated by Toledo Edison personnel to ensure all bristles were l
l removed from the steam generator. The material of the wire bristles was not known at this time.
l Later that same day, eddy current examinations identified a tube in steam generator B was obstructed, and FTI personnel initiated Nonconformance Report (NCR)98-200 as required by the FTI QA Plan. The tube obstruction was pushed into the lower bowl of the steam generator, where it was discovered that this obstruction was a wire bristle similar to those discovered on the D
Docket Number 50-346 i
License Number NPF-3 Serial Number 1-1168 Attachment Page) upper steam generator tube sheet. Another wire bristle was also found in the lower bowl of the B steam generator and removed. The material of the wire bristle was then evaluated to determine t
the effects of any potentially undiscovered bristles on the Reactor Coolant System. When it was determined that the wire bristle was made of carbon steel, the origination of the wire bristles was traced to the wire brush that had failed during cleaning of the steam generator stud holes. At this time it was not recognized that the use of a carbon steel brush constituted a procedural violation.
The fact that a procedural violation had occurred in the use of a carbon steel brush on April 14, 1998, was not realized until FTI personnel were interviewed by Toledo Edison personnel and the NRC inspector on May 6,1998.
s Corrective Steos Taken and Results Achieved When the wire bristles were identified by video camera to be present on steam generator B tube sheet on April 18,1998, they were entered into the FTI Open Systems Log for Steam Generator Activities. After determining the wire bristles had been introduced during the current refueling outage, PCAQR 1998-0781 was initiated on April 25,1998. Upon discovery of a wire bristle inside a steam generator B tube and determination that the wire bristle was from a carbon steel wire brush, all steam generator tool boxes were inspected. The four carbon steel brushes discovered in the manway tool box were discarded based on the common knowledge that carbon steel brushes should not be used due to their likelihood of failure. All steam generator activities involving the use of wire brushes had been completed by this time, so no further actions were necessary to ensure carbon steel brushes were not used.
A thorough video inspection of steam generator B was performed to locate all potential wire bristles in addition to the 100 percent eddy current examination of the steam generator. All identified wire bristles were removed from the upper bowl of steam generator B. The one wire bristle discovered in the tubes of steam generator B was removed, and the lower bowl was thoroughly vacuumed to remove all wire bristles. These actions were completed on May 2,1998.
On May 6,1998, after learning that a procedural violation had occurred in the use of a carbon steel wire brush, NCR 98-218 was initiated by FTl personnel. This NCR was also tracked along with NCR 98-0200 under PCAOR 98-0781, which was revised to address the procedural noncompliance.
Corrective Stens Taken to Avoid Further Violations l
The FTI procedure used for steam generator manway removal and installation will be clarified to specifically delineate that only stainless steel or nylon brushes shall be used for stud hole maintenance. Additionally, the procedure will be revised to reflect that if a brush to be used for this task is not marked, or there is no reasonable assurance a brush is of the proper material, the brush will be discarded. This procedure will be revised prior to the next refueling outage, which l
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Docket Number 50-346 License Number NPF-3 Serial Number 1-1168 Attachment Page 4 is currently scheduled for April,2000. Training on the revised procedure and proper brush material will be performed during the next refueling outage for the workers specifically involved in steam generator work. This training will reinforce that the use of the proper brush material is a procedural requirement.
Based upon the described sequence of events, Toledo Edison believes that reasonable corrective actions were taken in accordance with governing procedures, based upon the circumstances and information available. Therefore, no corrective steps are necessary in relation to the corrective action process at the DBNPS.
Date When Full Compliance will be Achieved Full compliance was achieved on May 6,1998, when NCR 98-218 was initiated by FTI personnel to document the procedural noncompliance of using a wire brush of the wrong material to clean the steam generator stud holes. This NCR and NCR 98-200, which was initiated on April 25,1998, to document the concern of the wire bristles inside the steam generator, are being tracked by PCAQR 1998-0781, which was also initiated on April 25,1998.